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针对目前集约化农业生产中氮肥用量盲目偏高、氮素利用率低、土壤及肥料中氮素以温室气体N2O形式的排放量增加等问题,采用田间试验研究了不同氮肥水平(150、225、300kg·hm-2)配施双氰胺(DCD)对华北地区集约化农田冬小麦-夏玉米轮作系统N2O排放的影响,并分析了其经济效益.结果表明:在整个轮作系统中,不同氮水平配施DCD处理的N2O排放通量减小25.6%~32.1%,N2O年度累积排放量降低23.1%~31.1%.土壤N2O排放通量与表面温度和湿度均呈显著指数相关,且湿度对小麦季N2O排放的影响大于玉米季,而温度对玉米季的影响大于小麦季.施用DCD后,小麦、玉米产量分别增加16.7%~24.6%和29.8%~34.5%,两季作物经济收益平均增加7973.2元·hm-2.因此,合理氮肥用量配施DCD既可以保证作物产量、提高经济效益,又可以减少N2O排放.综合考虑环境效益与经济效益,本试验条件下中量氮肥配施双氰胺(N总量225 kg·hm-2)是一种适宜在华北地区推广的优良氮肥管理模式.
Aiming at the problems such as blindly high nitrogen fertilizer usage, low nitrogen utilization rate and increased nitrogen emission from soil and fertilizer in the form of greenhouse gas N2O in intensive agricultural production, field experiments were conducted to study the effects of different nitrogen fertilizer levels (150, 225, 300kg · hm-2) combined with dicyandiamide (DCD) on N2O emission from intensive winter wheat-summer maize rotation system in North China, and analyzed its economic benefits.The results showed that in the whole rotation system, different nitrogen levels N2O emission fluxes with DCD decreased by 25.6% -32.1% and cumulative N2O emissions decreased by 23.1% -31.1%. Soil N2O fluxes were significantly and exponentially correlated with surface temperature and humidity, The effect of N2O emission was more than that of maize season, while the effect of temperature on maize season was greater than that of wheat season. After applying DCD, the yield of wheat and maize increased by 16.7% -24.6% and 29.8% -34.5%, respectively, and the economic profit of both crops increased by 7973.2 yuan · Hm-2 Therefore, a reasonable amount of nitrogen fertilizer combined with DCD can not only ensure crop yield, improve economic efficiency, but also reduce N2O emissions.Considering the environmental benefits and economic benefits, under the conditions of this experiment medium amount of nitrogen fertilizer with dicyandiamide N total 225 kg · hm-2) is an excellent nitrogen management mode suitable for promotion in North China.